Electric heater.



l Witnesses: i Inventor:

W. S. ANDREWS.

ELECTRIC HEATER.

APPLICATION FILED JAN. 14, 1911.

1,022,016. Pacente Apr..2,1912.

2 SHEETS-SHEET 1.

mmm unimi llll Il William 5.3Tndrews, I

by 2 t Y His Dfttorney.'

W. S. ANDREWS.

ELECTRIC HEATER.-

A'PPLIOATION FILED 1.111,14, 1911.

1,022,01 6. Patented Apr. 2, 1912.

2 SHEETS-SHEET 2.

Fig. 4.

I /7 "umm m'llllllmlllmnmmgi Witnesses: Inventor:

William. S. JTndrews,

His fttorneg.

f UNITED sTATEs PATENT 4oEEIoEf f WILLIAM s. ANpEEwsfoE so'HENECTAnY, NEW Yonx, AssIeNoETo GENERAL ELECTRIC COMPANY, A CORPORATION E NEW Yoan .ELECTRIC HEATER..

application fuga January 14;A 1911. serial No. 602,604.

To all whom 'it may concern:

Be it known that I, WILLIAM S. ANDREWS, la citizen of the United Stat/es, residing at Schenectady, county of Schenectady, State of New York,'have invented certain new and v useful Improvements in Elect-ric Heaters, of I which the followingis a specication.

electrically heated flatirons and the like. In

- devices of this sort it is-often desirable that i lture.

some means be provided whereby the heat will be cut off from 'the ironin case the temperature exceeds a certain degree.

In my previous application, Serial No. 538,729, filed January 18,1910, I have disclosed an electric atiron in which an automatic switch is provided for cutting out the heating unit at a redetermined tempera- In said app ication I also provide means for again clo'sing the switch as well as means whereby the switch may be opened by the operator at any time. While this arrangement is perfectly satisfactory for general lpurposes, it has been found that under some conditions it is unsatisfactory to have the parts so arranged that the two contacts can be brought' together by the voperator so as to close the switch, although the switch can not be closed permanent-ly; that is, the operator may try to close the switch and doing so draw an injurious arc on the contacts., In carrying out my present invention, therefore, I overcome thisv objection by providing means whereby after the switch has once opened it cannot be closed until the temperature has dropped to a predetermined poi-nt. The means for accomplishing this object may be in the nature of a thermostatic element which, as so0n as nthe switch opens, acts as a barrier to prevent jthe closing of the switch. The arrangement is preferably such that thel switch is latched closed and a thermostat' is-arranged to trip the latch. Means may also be provided whereby the circuit may be pened at any time bythe operator and can' be again closed by the operatorif the temperature is not excessive.

Specification of Letters Patent.

. which coperates wardso as to open the switch.

Patenteanpr. 2, 1912.

Other objects and purposes of my invention will appear in the course of the following specification in which I have `shown my invention embodied in concrete-mechanism for purposes of illustration. A

vIn the accompanying drawing illustrating one embodiment of my invention, Figure 1 is a. side elevation of my flatiron with the easing in section so as to show the operating parts; Fig. 2 is a plan view of the iron with the casing removed and the switch closed; Fig. 3 is a similar view with the switch open;v and Fig. t isa diagrammatic lperspective view showing the circuit connections. Y

Referring to the. drawings, the heat-ing element 10 is provided for heating the base 11 of the iron in theusual way. .This heating unit is not shown in its structural relation with the iron, since it is not a feature of my invention and any form of unit may be used if desired. The unit is held in place by the plate 12 secured to the base by the screws 13. Mounted upon the plate 12 are the switch parts and other cooperating mechanism. A's shown, the switch consists of two spring members 14 and 15 which normally assume the open position lshown in Figs. 3 and 4. The switch is closed by turning the rod 16, which in turn operates the member 17 to close the switch. In order to latch this switch closed there is provided a resilient thermostatic member 18 which is adapted to bend toward and from the plate upon which it is mounted upon changes of temperature. On the lfree end of this ther-v mostatic member 18 is a beveled portion f19 with a projecting stud 2`0 on the member 17 'so as to`act holding the switch closed. As the member y17 is moved toward the position shown in Fig. 2, the stud 2Q presses upon the beveled portion 19 and forces the member 18 -downasa latch for ward. W'hen.v it reaches the end of thebeveled portion andthe switch is closed, the member 18 springs upward and holds the stud 2.0` in .place and thereby latches the .switch closed. The sliding rod 21 adapted" to be engaged by Athe .finger of the operator and arranged to force the member 18 down- With the arrangement thus far described,v

when the temperature riss above' a predes downwrd and release the member 17 ,f

termined point, the member I18 4will bend llt the switch has once opened the operator may jecting lip 24 on the member 17 rides over 'Fig 4. This prevents the closing of the switch until the temperature drops a prede- `ment is reached, when itv snaps upward and 'ing screws.

thereby allowing the switch to open. When turn the rod 16. so as to force the switch closed, but the switch cannot be latched closed until the element 18 lis again bent upward by the cooling of the iro'n. The act o the operator in attempting to close the switch, and perhaps making the attempt several times, may injure the contacts by drawing arcs on them. In order, therefore, to prevent any such closing of the contacts until the temperature has dropped to a point where the contacts should be closed and until vthe contacts can be latched closed, I provide a resilient thermostatic 'element v22. This element bends in the opposite direction from the element 18 so that when the temperature rises, the beveled end 23 bends upward intoA the path of the member 17. When, therefore, the switch opens,'the prothe end of the member 22., forcing it downward until the end of the thermosta-tic ele-4 latches the member in the position shown in termined amount, causing the member 22 to vbend downward. The result is that when the switch is once opened the rod 16 is locked against movement until such time as the switch shouldbe closed.V At this time the rod will be free to turn and close the switch. The temperatures at which both thermostatic elements operate may be regulated in the usual way by means of,/adjust It will be seen that I have provided a very simple arrangement whereby the current may be cut oif either automatically or manually and can be turned on again by the operator only when it is safe to have the current turned on.y This makes the apparatus proof against injury due to improper handling.

While I have shown my invention em-` bodied in concrete mechanism for purposes of illustration in accordance with the patent statutes, it should be understood that I do not limit my invention thereto except in so far as it islimited by the scope of the claims lannexed hereto, since various modifications thereof will suggest themselves to those skilled in the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of theUnited States, is

1. The combination with an electric heater, of a switch in the circuit thereof, and i means controlled by the temperature for y quent closing.

opening said .switch and thermostatically controlled means for preventing its subse- 2. The' combination with an electric heater, of a switch in the circuit thereof,

means for automatically opening said switch, and means controlled by the temperature for preventing thel closing thereof.

3. The combination with an electric heater, of a normally open switch in the c'ircuit thereof, means for holding said switch closed, and means controlled by the tempera` ture for-preventing the closure ofthe switch after it has opened. y

4, The combination with an electric heater, of a normally'open switch in the circuit thereof, a thermostatic element xfor holding said switch closed, and a vthermostatic element for preventing the closure of the switch after it has opened.

5. The combination -V with an electric heater, of a switch in the circuit thereof, means for causing said switch to automatically open, and thermostatic means for preventing the closure of the switch after it 'has opened.

6. The combination with an electric heater, of a switch in the circuit thereof, means for automatically opening said switch, manually operated means for closing said switch, and means controlled by the temperature for preventing the closure of the switch after it has opened.

7. The combination with an electric heater, of a switch in the circuit thereof biased to open position, means for closing said switch, and a resilientthermostatic element arranged to prevent the closure of said switch under certain conditions.

8. The combination with an electric heater, of a switchin the circuit thereof biased to open position, operating means forv closing said switch, and a' pair of thermostatic elements one of which holdsthe switch operating mechanism in open position under. -certaln temperature limitations' and the other holds it in closed position under other temperature limitations.

9. The combination with an electric heater, of a switch in the circuit thereof biased to open position, means for closing said switch, a resilient thermost-atic element for holding said switch closed, and a resilizent. thermostatic elemen't arranged to prevent the closure of said switch under certain conditions. l

In witness whereof, I have hereunto set my hand this 12th day of January, 191.1. WILLIAMS. ANDREWS. Witnesses:

BENJAMIN B. HULL, HELEN ORroRD. 

